The use of lock bolts for security purposes is widespread to control access to items stored in lockable, high-security enclosures, such as vaults, safes, and cabinets. A door to the enclosure is often secured against opening by one or more extended door bolts. An internal lock bolt prohibits the door bolts from being retracted using an external handle. When using a combination type lock, entry of a proper combination permits the exterior handle to be used to release the lock bolt and retract door bolts, thereby unlocking the door and permitting it to be opened.
Often, the combination lock or other security lock is coupled by a spindle to a mechanism that retracts the lock bolt; and therefore, the spindle must be large enough to apply the necessary forces to retract the lock bolt. Further, the spindle generally requires a clearance opening that is about 0.625 inch in diameter. The presence of the clearance opening provides an ingress point into the lock case that may be used by an intruder to insert an instrument to image the lock components otherwise hidden inside the lock case. Therefore, there is a need to provide a lock bolt system that eliminates the clearance opening.
Conventional lock bolt systems may use a self-contained power supply inside the lock case to power an actuator that retracts the lock bolt. Non-ideal conditions or multiple closely-spaced entries may deplete the power supply such that the lock bolt cannot be retracted upon entry of a proper combination. Increasing the capacity of the power supply may minimize such occurrences; however, a larger power supply increases the size of the lock case as well as the cost of the lock. Thus, there is a need to improve the reliability of a power supply in a lock bolt system without increasing its size or cost.
Thus, there is a need for a lock bolt system that does not have the disadvantages of the known lock bolt systems discussed above.